Email Encryption

Email encryption is a security measure that scrambles (encrypts) email content so that only the intended recipient can unlock and read the original message. In its encrypted form, an email is not legible to a human. You can only unlock encrypted emails with a private email key, which decrypts them back into the legible, original message.

This encryption process is commonly referred to as public key infrastructure (PKI). These key pairs can be created and distributed by various companies that operate as certificate authorities (CAs). They are trusted third-party businesses that provide proper certification for the public key and then enter the public key into a large directory of other public keys. The private key is always only known to the owner of that specific key.

• Email encryption is a way of securing email conversations to prevent those outside the email thread from obtaining sensitive, financial, or personal information.
• Secure email differs from encrypted email in that secure email protects the email account as a whole, whereas email encryption protects individual messages and their contents.
• Companies that forgo email encryption expose their internal networks to data breaches, compliance violations, and more.
• Implementing a sound email encryption policy improves cybersecurity, safeguards sensitive data, and strengthens your relationship with clients and other stakeholders.

When an email is sent, it is encrypted by a computer using the public key. This turns its contents into a complex, indecipherable scramble that is very difficult to crack. This public key cannot be used to decrypt the message, only to encrypt it. Only the person with the proper corresponding private key can decrypt the email and read its contents.

Here's how the email encryption process works:

1. The sender uses the recipient’s public key to encrypt the email message.
2. The encrypted message is sent over the internet.
3. When the recipient receives the message, they use their private key to decrypt it.

This system ensures that only the intended recipient, who possesses the matching private key, can read the encrypted message. Many email encryption protocols, such as Pretty Good Privacy (PGP) and Secure/Multipurpose Internet Mail Extensions (S/MIME), use this public key infrastructure. These protocols not only encrypt the message content but can also provide digital signatures to verify the sender's identity.

In addition to asymmetric encryption, email encryption often involves transport layer security (TLS) to protect messages in transit between email servers. TLS encrypts the connection, making it difficult for attackers to intercept messages as they travel across the internet.

While email encryption significantly enhances security, it's important to note that it typically only protects the message content. Metadata, such as sender and recipient addresses, may still be visible.

How is secure email different from encrypted email?

Secure email and encrypted email are related but distinct concepts.

Secure email is a broader term encompassing various security measures for email communications, including authentication, anti-phishing tools, and malware protection.

Encrypted email specifically refers to the process of converting email content into an unreadable format using encryption techniques.

Whereas secure email protects the overall email system and account, encrypted email primarily safeguards the message content. Secure email methods often protect the email account rather than its content, using measures like strong passwords and multi-factor authentication. In contrast, encrypted email protects the message and its attachments even after being sent by making them unreadable to unauthorized parties.

Depending on your organization’s structure, you may use different styles or methods of encryption for your email. Here are some configurations to consider and how they operate.

Pretty Good Privacy (PGP)

PGP is an encryption program that provides cryptographic privacy and authentication for email communication. It uses a combination of symmetric key cryptography and public key cryptography. PGP enables users to encrypt messages, sign them digitally, or do both. It's known for its strong security but can be complex to set up and use.

PGP is often used by individuals and organizations requiring high levels of email privacy and security.

Secure Multipurpose Internet Mail Extension (S/MIME)

S/MIME is a widely used protocol for encrypting and digitally signing emails. It uses public key cryptography, where the sender encrypts the message with the recipient's public key. Only the recipient, with their private key, can decrypt and read the message.

S/MIME provides authentication, message integrity, and non-repudiation. It requires both sender and recipient to have digital certificates, making it suitable for organizations with established security infrastructures.

Transport Layer Security

TLS encrypts the connection between email servers, protecting messages in transit. It's a protocol that operates at the transport layer of the network stack, securing communication channels over the internet.

TLS is widely implemented by email providers and offers automatic encryption without user intervention. However, it only protects messages while they’re moving between servers, not when they’re stored on the sender’s or recipient’s devices or email servers.

Advanced Encryption Standard (AES)

AES is a symmetric encryption algorithm widely used in various security applications, including email encryption. It uses the same key for both encryption and decryption, making it fast and efficient. AES supports key sizes of 128, 192 and 256 bits, with longer keys providing stronger security.

In email encryption, AES is often combined with other protocols, such as PGP or S/MIME, to encrypt the actual message content.

Emails are an especially vulnerable access point for attackers looking to intercept messages and important information. Hackers can gain access to your most important personal information sent through email — like Social Security numbers (SSNs), bank account numbers, or login credentials. They also gain access to attachments or content that others have sent to you and have the ability to take complete control of your email account.

Emails are most vulnerable when sent over an unsecured public network, but they can also be vulnerable within a more secure setting such as a company network. Encryption is an important added security measure that ensures that even if a message is intercepted, its information cannot be accessed. By using the public/private key pair system, email encryption also helps verify the authenticity of the sender and recipient of the message.

The risks of unencrypted emails are severe and far-reaching. Data breaches resulting from compromised emails can expose sensitive corporate information, leading to financial losses and reputational damage. Identity theft is another significant threat, as cybercriminals can use stolen personal information to open fraudulent accounts or make unauthorized transactions.

Email encryption offers significant benefits to individuals and organizations alike.

Individuals can use email encryption to safeguard personal information, financial details, and private communications.

Email encryption benefits businesses across various sectors, including the health care, finance, legal, and technology industries. It helps them maintain client confidentiality, protect intellectual property, and comply with data protection regulations.

For example, financial institutions rely heavily on encrypted emails to protect client financial information and prevent fraud, while law firms use encryption to maintain attorney-client privilege and protect sensitive case information.

Email encryption is also prominent in healthcare settings, as unencrypted emails containing patient data can result in Health Insurance Portability and Accountability Act (HIPAA) violations and hefty fines. For example, a healthcare provider sending unencrypted patient test results could inadvertently expose protected health information.

As cyberthreats continue to evolve, email encryption will remain an essential tool for anyone looking to bolster their digital security and protect valuable information — especially enterprise-level organizations.

Enterprise email encryption

For enterprise-level organizations, implementing user-friendly email encryption solutions is crucial to secure communication and mitigate cyberthreats. As a primary communication channel, email is a significant vulnerability point for data breaches and cyberattacks. Robust encryption methods can go a long way in helping companies protect sensitive information, maintain client confidentiality, and safeguard intellectual property.

User-friendly solutions are particularly important, as they encourage widespread adoption among employees. And widespread adoption significantly reduces the risk of human error.

When comparing email encryption solutions, look for systems that can seamlessly integrate with existing email platforms, providing end-to-end encryption without disrupting workflow.

Barracuda Email Protection secures your mail by encrypting it during transport to the Barracuda Message Center, encrypting it at rest for storage in the cloud, and providing secure retrieval by your recipients through HTTPS Web access.

Do you have more questions about email encryption? Contact our team today to schedule an Email Protection demo today.